ICS 1 sem1 block 4

Biogeochemical cycles Packet

Standards ES 7 a, b, c, d

To be accepted for grading it must be in order and signed

Parent/Guardian: Print_________________________________

Sign______________________________________ Date_______

Content Objective

Students know the carbon cycle of

photosynthesis and respiration and the nitrogen

cycle. Students know the global carbon cycle:

the different physical and chemical forms of

carbon in the atmosphere, oceans, biomass,

fossil fuels, and the movement of carbon among

these reservoirs. Students know the movement

of matter among reservoirs is driven by Earth’s

internal and external sources of energy.

Students know the relative residence times and

flow characteristics of carbon in and out of its

different reservoirs.

Language Objective

Understand the proper use of the words, carbon dioxide, oxygen nitrogen, photosynthesis and respiration.

Be able to explain the path of carbon through the world using key concepts such as calcification, bicarbonate’s,

greenhouse effect, and fixation.

Explain the internal and external heat sources of the Earth which control energy movement, flow properties, and

reservoir times. Explain the materials for, the creation process, and the storage of fossil fuels. Fossil fuels are

the major source of energy for today, coal, gasoline, natural gas and oil are all fossil fuels. Be able to Describe

the path of the carbon among these components and how this influences the environment.

Period_______

Name

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1. Cover Sheet / Agree-Disagree 2. WCW-warm-up, critical thinking, wrap-up 3. Standard ES 7 a, b, c, d 4. Vocabulary- Biogeochemical Cycles of Earth 5. Carbon Cycle Notes 6. Carbon Cycle Handout

7. Nitrogen cycle Notes 8. Nitrogen cycle Handout 9. Global Carbon Cycle Notes 10. Global Carbon Cycle Handout 11. Matter-Energy Notes

12. Matter-Energy Handout 13. Study-guides 14. CST-Practice-Questions

WCW- #2

Warm-up 9/24 even 9/25 odd

Describe the cycle in the picture…

Critical thinking

When the amount of oxygen doubles, the amount of carbon dioxide …

Wrap-up

Carbon enters the atmosphere by… and leaves the atmosphere by…. The two processes are related by…

Warm-up /27 even or 9/28 odd

In the process of Photosynthesis, Sunlight + __?__ + water/nutrients

Creates oxygen + ___?___

Critical thinking

How are decomposers and producers involved in the carbon and

nitrogen cycles?

Wrap-up

Describe how nitrogen can be “fixed” and “unfixed” .

Warm-up 10/1 even 10/2 odd

Critical thinking Describe the Relation between Fossil Fuel combustion, Tropical deforestation and global carbon cycle

CO2 sources Flux (Gt C/yr)

Fossil fuel combustion 5.5 ± 0.5

Tropical deforestation 1.6 ± 1.0

Wrap-up

From standard 7b bottom

This release of _______ has increased the concentration of ______ dioxide in the atmosphere. ______ dioxide

is a primary g_________ gas, and its concentration in the atmosphere is tied to climatic conditions.

Warm-up 10/2 odd 10/3even

Explain the cycle of Carbon through Photosynthesis and

respiration in three steps.

Critical thinking under warm-up

Explain the heat provided by a meteor hitting the Earth.

(i.e. explain how it adds heat)

Animal carbon dioxide oxygen sucrose

Wrap-up

Cell Respiration: – An ________ produces _______ and consumes ________ in its metabolism

of food. _______ is a typical food and a metabolic reaction can be represented by: C6H12O6 + 6O2 6 CO2 + 6 H2O

Use the pictures to help you

You have it in the packet

Example answer beginning

1 Ingredients…

2 Process…

3 Outcome…

ES 7. Each element on Earth moves among reservoirs, which exist in the solid earth, in oceans, in the

atmosphere, and within and among organisms as part of biogeochemical cycles. As a basis for

understanding this concept: ES 7. a. Students know the carbon cycle of photosynthesis and respiration and the nitrogen cycle.

Carbon and nitrogen move through biogeochemical cycles.

The recycling of these components in the environment is crucial to the maintenance of life. Through

photosynthesis, carbon is incorporated into the biosphere from the atmosphere. It is then released back into the

atmosphere through respiration. Carbon dioxide in the atmosphere is dissolved and stored in the ocean as

carbonate and bicarbonate ions, which organisms take in to make their shells. When these organisms die, their

shells rain down to the ocean floor, where they may be dissolved if the water is not saturated in carbonate.

Otherwise, the shells are deposited on the ocean floor and become incorporated into the sediment, eventually

turning into a bed of carbonate rock, such as limestone. Uplifted limestone may dissolve in acidic rain to return

carbon to the atmosphere as carbon dioxide, sending calcium ions back into the ocean where they will

precipitate with carbon dioxide to form new carbonate material. Carbonate rocks may also be subducted, heated

to high temperatures, and decomposed, returning carbon to the atmosphere as volcanic carbon dioxide gas.

Carbon is also stored in the solid earth as graphite, methane gas, petroleum, or coal. Nitrogen, another element

important to life, also cycles through the biosphere and environment. Nitrogen gas makes up most of the

atmosphere, but elemental nitrogen is relatively inert, and multicellular plants and animals cannot use it directly.

Nitrogen must be “fixed,” or converted to ammonia, by specialized bacteria. Other bacteria change ammonia to

nitrite and then to nitrate, which plants can use as a nutrient. Eventually, decomposer bacteria return nitrogen to

the atmosphere by reversing this process.

ES 7. b. Students know the global carbon cycle: the different physical and chemical forms of carbon in the

atmosphere, oceans, biomass, fossil fuels, and the movement of carbon among these reservoirs.

The global carbon cycle extends across physical and biological Earth systems. Carbon is held temporarily in a

number of reservoirs, such as in biomass, the atmosphere, oceans, and in fossil fuels. Carbon appears primarily

as carbon dioxide in the atmosphere. In oceans carbon takes the form of dissolved carbon dioxide and of

bicarbonate and carbonate ions. In the biosphere carbon takes the form of sugar and of many other organic

molecules in living organisms. Some movement of carbon between reservoirs takes place through biological

means, such as respiration and photosynthesis, or through physical means, such as those related to plate

tectonics and the geologic cycle. Carbon fixed into the biosphere and then transformed into coal, oil, and gas

deposits within the solid earth has in recent years been returning to the atmosphere through the burning of fossil

fuels to generate energy. This release of carbon has increased the concentration of carbon dioxide in the

atmosphere. Carbon dioxide is a primary greenhouse gas, and its concentration in the atmosphere is tied to

climatic conditions.

ES 7. c. Students know the movement of matter among reservoirs is driven by Earth’s internal and

external sources of energy.

The energy to move carbon from one reservoir to another originates either from solar energy or as heat from

Earth’s interior. For example, the energy that plants use for photosynthesis comes directly from the Sun, and the

heat that drives subduction comes from the solid earth.

ES 7. D Students know the relative residence times and flow characteristics of carbon in and out of its

different reservoirs.

Carbon moves at different rates from one reservoir to another, measured by its residence time in any particular

reservoir. For example, carbon may move quickly from the biomass to the atmosphere and back because its

residence time in organisms is relatively short and the processes of photosynthesis and respiration are relatively

fast. Carbon may move very slowly from a coal deposit or a fossil fuel to the atmosphere because its residence

time in the coal bed is long and oxidation of coal by weathering processes is relatively slow.

Vocabulary item #4

1. Reservoirs – container, holding area

2. Photosynthesis- process that uses sunlight, carbon dioxide water and nutrient sto make oxygen and

glucose

3. Biosphere-specific region on Earth that harbors life

4. Respiration-breathing, oxygen in carbon dioxide out

5. Carbon dioxide-

6. Limestone-

7. Acid rain-

8. Subduction-

9. Fossil fuels-

10. Bacteria-

11. Biomass-

12. Sugar-

13. Greenhouse gas-

14. Matter-

15. Solar Energy-

16. Convection cells-

17. Residence times-

18. Atmosphere-

19. Oxidation-

20. Weathering-

Notes: item #5 Carbon Cycle of Photosynthesis & Respiration

http://www.vtaide.com/png/photosynthesis.htm Photosynthesis -plants make food

photo = light synthesis = putting together

Plants take in carbon dioxide from the air water/nutrients from the soil in the presence of light

energy and chlorophyll to produce sugar (glucose) and oxygen. Chlorophyll is the green pigment

found in plants. Both chlorophyll and light energy need to be present for photosynthesis to take

place, but they are not used up in the process.

Some of the sugar produced during photosynthesis is used by the plant for its life

processes (such as growing and reproducing

carbon dioxide +

water

chlorophyll →→→→→→→→

light energy

sugar

(glucose) +

oxygen

); the excess is converted mainly to starch and stored in various plant parts which may be used as

food by animals and humans. Oxygen produced during photosynthesis replenishes the oxygen

that was used up by living things during respiration This cycle of photosynthesis and respiration

maintains the balance of carbon dioxide and oxygen on earth.

Photosynthesis Respiration

Occurs in the presence of light (and

chlorophyll in plant cells)

Occurs at all times in cells

Requires energy (light) to make

sugar (glucose)

Releases energy from sugar

Complex substances (sugar) are

formed from simpler ones.

Complex substances (sugar) are

broken down into simpler ones.

Carbon dioxide and water are the

raw materials

Carbon dioxide and water are the

waste products.

Oxygen is given out. Oxygen is taken in.

Item 6 Carbon Cycle Worksheet Name ________________________ Class _____

1.What inorganic molecule is carbon normally found in? ________________________

2.Name an organic molecule that carbon is found in. ________________________

3.What molecule do trees get their carbon from? ________________________

4.Where do primary consumers get their carbon from? ________________________

5.What process adds carbon to the atmosphere? ________________________

6.What process removes carbon from the atmosphere? ________________________

7.How does oxygen get into the water? ________________________

8.What do producers produce? ________________________

9.List 3 groups of producers? ________________________

________________________

________________________

10.What group eats producers? ________________________

11.How does carbon get back into the atmosphere from ________________________

the food we eat?

12.Where do secondary consumers get their carbon from? ________________________

13.Where does an animal’s or plant’s carbon go when it ________________________

dies?

14.Why should the amount of carbon in the atmosphere ________________________

stay the same?

15.How is extra carbon getting into the atmosphere today? ________________________

16.List 3 ways that we could reduce the extra carbon that is getting into the atmosphere.

1.

2.

3.

17. In the space below, draw your own version of the carbon cycle. Use arrows to show which way the carbon is

going.

Label - Producers, Primary Consumers, Secondary Consumers

CARBON CYCLE

Notes: Nitrogen item #7

Nitrogen (N) All need nitrogen to survive

Huge amounts in the atmosphere, but most animals and plants can’t get it

It needs to be fixed i.e. put into useful compound

Then it can move through the cycles and organisms in an ecosystem

Where Can You Find It?

Main sources of nitrogen atmosphere

The other source of nitrogen is in the nitrates of soil.

Nitrogen can be converted into useful nitrate compounds by bacteria, algae, and

even lightning.

Once in the soil, the nitrogen becomes biologically accessible

Borrowing Nitrogen

Plants are the main users of nitrogen in the soil.

They are able to take in the nitrates through their root system. Once inside the plant,

the nitrates are used in organic compound that let the plant survive.

Organic compounds have carbon atoms.

Compounds might be proteins, enzymes, or nucleic acids

Herbivores convert amino acids into new proteins.

Nitrogen atoms are returned to the soil in feces and Decaying matter

Item # 8 Nitrogen Cycle Worksheet Name ________________________ Class _____

1. Why do plants and animals need nitrogen (N)?

2. What molecule in the atmosphere is nitrogen normally found in?

3. What molecule in the ground is nitrogen found when there is no oxygen around?

4. What molecule in the ground is nitrogen found when there is oxygen around?

5. What organic molecule is nitrogen found in?

6. What are 2 ways that atmospheric nitrogen gets into the ground?

7. What organisms (living things) do the nitrogen fixation for plants?

8. Why don’t farmers have to put nitrogen fertilizer on soybeans?

9. Where do plants get their nitrogen from?

10. How do primary consumers get their nitrogen from?

11. How do secondary consumers get their nitrogen from?

12. What’s another term for a primary consumer?

13. What’s another term for a secondary consumer?

14. Where does an animal’s or plant’s nitrogen go when it dies?

15 Who breaks the dead organisms’ body back into inorganic nitrogen?

In the space below, draw your own version of the nitrogen cycle. Use arrows to show which way the nitrogen is

going.

Label – Producers(Plants), Nitrogen Fixing Bacteria, Primary Consumers,

Secondary Consumers, Decomposers

NITROGEN CYCLE

Item # 9 The Global Carbon Cycle

More than any other element, carbon is associated with our changing

climate.

Where does carbon reside?

What trends in atmospheric CO2 have been observed?

What regulates the flow of carbon between its various reservoirs?

Is it possible that feedback mechanisms regulate the amount of

atmospheric CO2?

How is carbon cycled at a global scale? • Cell Respiration: – An animal produces carbon dioxide and consumes oxygen in its metabolism of food.

Glucose is a typical food and a metabolic reaction can be represented by:

– C6H12O6 + 6O2 6 CO2 + 6 H2O

• Photosynthesis: – A plant and green bacteria, on the other hand, produces oxygen and consumes carbon

dioxide. – Energy in the form of electromagnetic radiation (or photons) is supplied so that the low-

energy-content carbon dioxide can be converted to high-energy-content glucose. – An overall reaction for the complicated multi-step photosynthesis reaction can be

represented by:

– 6CO2 + 12H2O C6H12O6 + 6O2 + 6H2O

Item # 10 Global Carbon Cycle

1. If 100 kg of carbon dioxide is photosynthesized, does this contribute to the amount of free oxygen (O or O2)

in the atmosphere or deduct from it? How much oxygen is produced or destroyed? How much carbon is

produced or destroyed?

Photosynthesis generates free oxygen. The atomic weight of CO2 is 44 with 12 AMU from Carbon and 32 AMU

from Oxygen. If 100 kg of CO2 is photosynthesized, 72.7 kg of free oxygen (2 atoms for every one molecule of

CO2) is produced and 27.3 kg of Carbon (in the form of carbohydrates) is produced. (The carbohydrates would

weight 68.25 kg.)

The reaction for photosynthesis is:

CO2 + H2O + hv --> CH2O + O2

2. During the early evolution of the earth, what was an important source of free oxygen? Did it eventually help

sustain a new processes of oxygen production? What was that new process?

Free oxygen may have been created by photodissociation of water vapor in the early Earth. This created free

oxygen and eventually ozone which enabled plantlife and photosynthesis to exist on land. It is probably that

photosynthesis already existed in the oceans before the ozone layer.

3. If under global warming, the amount of photosynthesis decreases (due to reduced extent of boreal forests)

from 200 Gt-O/yr to 100 Gt-O/yr, how long will the oxygen in the atmosphere last?

In steady state, photosynthesis and respiration are in balance. If photosynthesis were to decrease by 50%, this

represents a net sink of 100 Gt-O/yr. Given that the reservoir is 1.1x106 Gt. Oxygen would last 1.1x106/100

years or about 10,000 years.

4. Identify at least one rapid process not mentioned in class that may constrain the amount of atmospheric

oxygen between certain minimum and maximum bounds.

Fire may help constrain the levels of atmospheric oxygen. If oxygen levels become too high, fires will burn

stronger and longer thus depleting atmospheric O2. If oxygen levels decrease, fewer fires will occur and they

will not burn as strongly. It is believed that this has helped constrain levels of oxygen in recent millenia to

between roughly 10% and 30%.

5. Why is the amount of "free" oxygen in the atmosphere related to the amount of carbon in the atmosphere? If

one increases the amount of carbon in the atmosphere does this increase or decrease the amount of "free"

oxygen?

Carbon in the atmosphere is precominantly found in CO2. If carbon reacts (to form sediments for example) this

releases free oxygen in the atmosphere. If carbon reacts to re-enter the atmosphere (through respiration for

example) this removes oxygen from the atmosphere. If one were to increase the amount of carbon in the

atmosphere, this would decrease the amount of free oxygen.

1. Estimate the time scale for emptying the sedimentary reservoir by geologic processes given that volcanic

outgassing amounts to about 0.05 Gt C/yr and the reservoir is contains roughly 60 million Gt-C.

Volcanic outgassing is a process that depletes sedimentary carbon and would deplete a reservoir of 60 million

Gt in about 1.2 billion years.

2. If the oceans were to stop absorbing carbon (due to saturation for example), what percentage increase in

atmospheric carbon (per year) would initially occur?

The oceans absorb about 50 GtC per year. If this were to stop, the atmosphere would gain 50 GtC per year

which is about 6.7% of the 750 GtC held by the atmosphere. If you tried to use the numbers from Table 10.10 it

would be incorrect because that Table shows the net imbalance between dissolution and evaporation of carbon,

not the net dissolution.

3. What carbon compounds are produced by photosynthesis and exploited by living beings for energy? What

reactants are required to generate these compounds?

Carbohydrates (C-H2O) and oxygen are produced by photosynthesis from the reactants of CO2, H2O and light.

4. If the deep ocean circulation were to accelerate and thus increase the existing exchange of carbon with

surface oceans, what impact might this have on the surface ocean and, eventually, the atmosphere?

In the net, the exchange of carbon between the deep ocean and the surface ocean contributes bicarbonate ions

to the surface ocean. If upwelling were to increase the surface ocean would have more bicarbonate ion and

would eventually saturate, reducting the amount of CO2 that would disolve in the upper ocean and atmospheric

carbon levels would eventually increase.

5. Propose an investigation aimed at reducing the amount of carbon dioxide in the atmosphere based on what

you know about the long-term or short-term carbon cycles. To do so, simply state a process relevant to

atmospheric CO2 levels and suggest an hypothesis you'd like to investigate for modulating its rate.

There are many possible answers to this. For example, one might attempt to modulate the rate of carbon uptake

by the surface oceans by enhancing photosynthesis in the surface oceans. Currently, experiments that contribute

iron to the upper ocean are exploring this possibility. Many other experiements can be envisioned.

Notes matter energy item#11

The movement of matter among reservoirs is driven by Earth’s internal and external sources of energy

The

relative

residence

times and

flow

characteri

stics of

carbon in

and out of

its

different

reservoirs

Carbon

moves at

different

rates from

one

reservoir

to another,

measured

by its residence time in any particular reservoir.

Example

Carbon may move quickly from the biomass to the atmosphere and back because its residence time in

organisms is relatively short and the processes of photosynthesis and respiration are relatively fast.

Carbon may move very slowly from a coal deposit or a fossil fuel to the atmosphere because its residence time

in the coal bed is long and oxidation of coal by weathering processes is relatively slow.

The energy to move carbon from one reservoir to another originates either from

Internal sources of energy External sources of energy

Heat in the Earth

1 source Remnants of heat from impacts

with planetesimals early in Earth's history.

Impacts with large bodies such as these

(including the impact which led to the

formation of the moon) trapped the

thermal energy of the collision in the

surrounding rock of the planet, and may

have been enough in certain

circumstances to completely melt the

early Earth.

2 source remnant of an early Earth event

known as the Iron Catastrophe.

With much of early Earth still molten,

denser metals, particularly iron and nickel,

migrated to the center of the planet.

Tremendous amounts of frictional heat

was created, enough to completely melt

the planet once again.

3 source from compression due to gravity.

4 source the decay of radioactive

elements. This source of heat is gradually

declining due the decreasing amounts of

radioactive isotopes, the decrease being

caused by the decay.

Ex

Driving force of subduction

Solar Radiation

The driving force of weather on Earth.

In the "water cycle", the sun is

responsible for evaporation of ocean

surface water. As this happens, the

water vapor rises. The combination of

the Earth's rotation and the changes in

atmospheric pressure is the primary

determinant for when and where the

rain comes down.

Ex

Driving Force of photosynthesis

1. V = d/t speed equals distance divided by time

Suppose the Speed of a molecule is 10% the speed of light or 30,000,000 meters per second. What is the time it

took to travel 1,000,000 m?

Item # 12 Matter energy Handout

1. Our atmosphere is ______ nitrogen gas.

2. Animals and plants cannot directly use all the nitrogen found in our ________________.

3. Only special bacteria can directly use nitrogen in our atmosphere and “fix” it so other organisms can

benefit. These bacteria are called ____________-_________ bacteria.

4. Higher organisms use nitrogen to make their _____________.

5. Animal waste decay by the action of bacteria which create _____________and __________ products

rich in nitrogen, and useful for plants to use again.

6. ______________ bacteria in the soil can break down the ammonia into the gaseous form of nitrogen,

which is not available for use by plants or animals.

7. In another part of the cycle, animals eat ____________ containing nitrogen, which is again returned to

the soil by animal _____________ or decaying ____________ and ___________.

8. Draw a diagram of the Nitrogen cycle using the words in the text box.

Oxygen Cycle

1. Plants release 430-470 billion tons of oxygen during process of _________________.

2. Atmospheric oxygen in the form of ___________ provides protection from harmful ultraviolet rays.

3. Oxygen is found everywhere on Earth, from Earth’s _____________ (rocks) to the ______________

where it is dissolved.

4. Oxygen is vital for ________________ by animals, a process which produces CO2.and water.

5. Oxygen is also necessary for the decomposition of ______________ into other elements necessary for

life.

6. Write the equation for respiration.

7. Draw a diagram of the Oxygen Cycle using the words in the text box.

Atmosphere 78% ammonia proteins denitrification

Nitrate nitrogen-fixing plants animal’s waste plants

Photosynthesis Ozone Waste Crust Oceans Respiration

Item # 13 is only on website

6. Nitrogen is essential to life because

A. It is needed for building proteins (growth)

B. It is breathed in by all life.

7. Plants get nitrogen from

A. Breathing it in

B. Absorbing it through roots from the ground

8. Nitrogen-fixing bacteria are important because

A. They turn nitrogen from the air into nitrogen compounds in the soil.

B. They are essential for plants being able to carry out photosynthesis.

9. During decomposition,

A. Bacteria use oxygen to produce nitrates from ammonium.

B. Bacteria produce the oxygen needed for photosynthesis.

10. Excess nitrates in water causes problems for the Chesapeake Bay because

A. They cause excessive cellular respiration in plants and animals, resulting in a large amount of carbon

dioxide production.

B. They cause excessive algae growth, blocking sunlight and reducing oxygen when it dies.

1. Carbon is essential to life because

A. It’s the most common element.

B. It is the molecule around which all the molecules of life are built.

2. Where do plants gets their supply of carbon?

A. Cellular Respiration

B. Photosynthesis

3. Where does the carbon for your body come from?

A. From eating plants and animals

B. From breathing it in

4. Where does the oxygen for your body come from?

A. From eating plants and animals

B. Photosynthesis in plants

5. Which of the following does not use up oxygen and produce carbon dioxide?

A. Cellular Respiration

B. Photosynthesis

Carbon Cycle (2 points each)

Use the following word bank to answer 11-14

a) CELLULAR RESPIRATION

b) GLUCOSE (CARBOHYDRATES)

c) EATING PLANTS

d) CO2

11. What inorganic molecule is carbon normally found in?

12. Name an organic molecule that carbon is found in.

13. What process adds carbon to the atmosphere?

14. Where do primary consumers get their carbon from?

Use the following word bank to answer 15-18

a) GROUND

b) PHOTSYNTHESIS AND RESPIRATION SHOULD BALANCE EACH OTHER OUT.

c) CELLULAR RESPRATION

d) PRIMARY CONSUMERS

15. How does carbon get back into the atmosphere from the food we eat?

16. Where do secondary consumers get their carbon from?

17. Where does an animal’s or plant’s carbon go when it dies?

18. Why should the amount of carbon in the atmosphere stay the same?

Nitrogen Cycle (2 points each)

Use the following word bank to answer 19-22

a) AMMONIA (NH3)

b) TO BUILD PROTEIN MOLECULES

c) NO3

d) N2

19. Why do plants and animals need nitrogen (N)?

20. What molecule in the atmosphere is nitrogen normally found in?

21. What molecule in the ground is nitrogen found when there is no oxygen around?

22. What molecule in the ground is nitrogen found when there is oxygen around?

Use the following word bank to answer 23-26

a) HERBIVORE

b) EATING ANIMAL PROTEIN

c) EATING PLANT PROTEIN

d) THE GROUND (NO3)

23. Where do plants get their nitrogen from?

24. How do primary consumers get their nitrogen from?

25. How do secondary consumers get their nitrogen from?

26. What’s another term for a primary consumer?

Item #14 CST prep

Carbon / Nitrogen Cycles Quiz

1. Carbon is essential to life because

A. It’s the most common element.

B. It is the molecule around which all the molecules of life are built.

C. It is found in inorganic molecules.

D. Plants can’t live without it.

2. Where do plants gets their supply of carbon?

A. Cellular Respiration

B. From the ground

C. From the waste of animals

D. Photosynthesis

3. Where does the carbon for your body come from?

A. Cellular Respiration

B. From breathing it in

C. From eating plants and animals

D. Photosynthesis

4. Where does the oxygen for your body come from?

A. Cellular Respiration

B. From the ground

C. From eating plants and animals

D. Photosynthesis in plants

5. Which of the following does not use up oxygen and produce carbon

dioxide?

A. Cellular Respiration

B. Photosynthesis

C. Decomposition

D. Burning fossil fuels like coal and oil

6. Nitrogen is essential to life because

A. It is the most common element.

B. It is the molecule around which all the molecules of life are built.

C. It is breathed in by all life.

D. It is needed for building proteins (growth)

7. Plants get nitrogen from

A. Breathing it in

B. Absorbing it through roots from the ground

C. Basic photosynthesis

D. Cellular Respiration

8. Nitrogen-fixing bacteria are important because

A. They turn nitrogen from the air into nitrogen compounds in the soil.

B. They are essential for plants being able to carry out photosynthesis.

C. They break up dead plants and animals in the soil.

D. They release excess nitrogen from the soil into the atmosphere.

9. During decomposition,

A. Bacteria use oxygen to produce nitrates from ammonium.

B. Bacteria produce the oxygen needed for photosynthesis.

C. Bacteria put oxygen back into the atmosphere.

D. Bacteria use oxygen to produce ammonium from dead material.

10. Excess nitrates in water cause problems for the Chesapeake Bay because

A. They cause excessive cellular respiration in plants and animals, resulting in a large

amount of carbon dioxide production.

B. They cause excessive bacteria growth resulting in too much oxygen which hurts

photosynthesis in plants.

C. They cause excessive algae growth, blocking sunlight and reducing oxygen when it

dies.

D. Nitrates are poisonous to fish, crabs, and oysters.